I would rather suggest you use only one or the other of the ciphers and use a key double the size of current. If you must use two ciphers, then use different keys for both of them.
And by the way, would someone crack your first ciphers key, the cracker would probably try the same key for the next cipher also as a first guess.
I'm not a cryptoanalyst, but I'd bet it's just the same which cipher you use in which order.

Apparently you will get some additional security each time you add an
encryption envelop, and usually it will result to some additional data...
Now, by using the same key for both, it is a bad idea only for humans not
for machines, not to mention that to decrypt 2nd time with different
algorithm, it most probably means that the hacker used social engineering
to get that info as well as the used algorithms to try and crack them. In
that case it would have taken less time for the hacker to continue social
engineering approach, rather than hitting the keyboard!
Most of the encryption algorithms are based on sophisticated math
transformations, but when you start coding them, it is plain and relatively
simple; therefore no security sensitive information is coded with one
single algorithm. Some times there are layers over layers (as long as the
data can be decrypted and the encoded result passes some indexes).

But consider this: how will the cracker know he has cracked the first (outer) key? The result is still going to look like random bytes, not significantly different from the original. The only way a key is known to have been cracked is if the resulting decryption is identifiable as usable data.

@Archer : This is the point I was making, if someone knows already that you
have two envelops to go for further analysis, this data has to come from
some person or part of the code used for encryption.
The most common tool to acquire this information is Social Engineering, in
which case, it would be stupid to brute-force the data to crack it!
If I was in the hacker's shoes, I would rather prefer to continue S.E. to
see what else I can get.
Also if SE is used, then there is a valid possibility to get the
credentials for privileged access, so why waste time on brute-force?

This is an older topic, but I suggest two-fish rather than blowfish.
Blowfish is still considered secure, but two-fish is superior in every way.

Wrapping two or three different encryption algorithms is accepted
practice and adds concideriably to security, however it also slows the
encryption/decryption considerably as well. Depending on what you are
doing, such as an encrypted boot partition with a weaker cpu, you may
find the speed intolerable. AES is not only highly secure, but very fast
even with 16 rounds and was chosen for that reason. Alone, AES is pretty
darn secure and gets a CPU boost with most modern chips, even entry
level chips.

You can follow up on this by looking up the algorithms on wikipedia, the
truecrypt website and Bruce Schneier's (co-creator of twofish and
blowfish) website.